1. Field of the Invention
This invention relates to a process for producing quinones. More specifically, it relates to a process for producing quinones corresponding to the anthracenes or alkylnaphthalenes used as starting materials which comprises reacting the anthracenes of alkylnaphthalenes with hydrogen peroxide.
2. Description of the Prior Art
Quinones are important substances as industrial chemicals. Unsubstituted quinones are used as raw materials for dyes, and alkyl-substituted quinones are useful as raw materials for dyes or as media in the production of hydrogen peroxide.
One conventional method for producing anthraquinones comprises reacting anthracenes with hydrogen peroxide in acetic acid. If it is attempted to increase the conversion of the anthracenes in this method in the absence of a catalyst or in the presence of a sulfuric acid catalyst, their selectivity to the anthraquinones is reduced. On the other hand, if an attempt is made to increase the selectivity to anthraquinones, the conversion of the anthracenes becomes lower. In either case, the yeilds of the anthraquinones based on the anthracenes are low. Furthermore, the present inventors found that when this method was applied to the production of alkyl-substituted quinones from alkyl-substituted anthracenes or alkyl-substituted naphthalenes, the yield was very low, and the range of application was limited.
On the other hand, when cerous carbonate was used as a catalyst in the above-described method, the yield was as high as 82%. But since the catalyst is expensive, this method is not advantageous from a practical standpoint.
Another conventional method involves reacting anthracenes with hydrogen peroxide in tertiary-butyl alcohol using osmium tetroxide as a catalyst. However, this method is also not feasible because of the high cost of the catalyst.
It is an object of this invention to provide a process for producing quinones, which has a wide range of application and is commercially very advantageous, and which can give quinones in good yields based on anthracenes or alkylnaphthalenes (to be referred to simply as yields) by a very simple step using an inexpensive and readily available catalyst, while maintaining good conversions of the anthracenes or alkylnaphthalenes (to be referred to simply as conversions) and good selectivities to quinones (to be referred to simply as selectivities).